1. Field of the Invention
The present invention relates to an air bag apparatus which causes a bag body to expand toward the side of an occupant upon sudden deceleration of a vehicle and to a bag body suitable for use in the air bag apparatus and, more particularly, to an air bag apparatus and a bag body provided with a stationary pad or the like so as to be in an immobile state.
2. Description of the Related Art
An air bag apparatus of a type that can be, for example, mounted on a steering wheel, comprises a starting apparatus which senses the sudden deceleration of a vehicle, an inflator which expels gas upon actuation of the starting apparatus, and a bag or the like which is expanded toward the side of an occupant by the gas expelled from the inflator.
On the inner circumferential surface of the bag, there are one or a plurality of straps which are usually made of cloth and are folded inside the bag when the air bag apparatus is in its inactive state, that is, when the bag is in the folded state. During the sudden deceleration of a vehicle, the bag tends to expand toward the side of the occupant in the form of a sphere. Because the length of the strap is shorter than the diameter of the inflated bag without the strap, the bag cannot expand to its fullest. Therefore, as shown in FIG. 8, bag 100 takes the shape of a flat sphere when expansion is completed. During the vehicle's sudden deceleration, the inertial movement of the occupant's head is such that it strikes the approximate center portion of the bag 100, thereby protecting the occupant from injury.
Since the air bag apparatus is to be used in combination with a seat belt apparatus provided in a vehicle, a primary object of the inflated air bag is to protect the head of the occupant.
However, in the case of bag 100, when expansion is completed and the shaped bag is in the form of a flat sphere, a problem arises in that an upper end portion 100A of the bag 100 excessively extends past the top of the head 102 of the occupant.
Further, since the bag of a conventional air bag apparatus is inflated in the form of a flat sphere as described above, so as to be interposed between the steering wheel and the occupant, the bag is made larger than necessary. Therefore, it is necessary to generate a large quantity of gas in order to inflate the bag instantaneously.